The way I see it, younger gamers or gamers who came late into the series (post-classic Fallouts) will enjoy the Bethesda titles more. The same goes for those who prefer free exploration as opposed to exploration but with a tight, gripping story.
I can't stand turn-based stuff, myself, it's a pet peeve of mine and there's no point in denying it: I find it boring and archaic, and no "but, groze, it's STRATEGIC, bro!" argument will win me over. Ever. Still, the first two Fallouts are one of the very few exceptions I'm willing to make. I love the fact they managed to tie gripping storytelling with free exploration, engaging setting, a non-black-and-white morality system and a multiple approach to quests design all in one. Sure, the graphics weren't groundbreaking even back then, and the Bethesda Fallouts look gorgeous, but they fail to nail pretty much everything else (especially Fallout 3).
Fallout 3 has a cool setting. But, to me, it's really all it has going for it. It falls prey to the usual "Bethesdification": they have awesome properties with complex lore and background, but turn everything into huge -- admittedly impressive -- kind-of-living worlds that the player is free to explore. But that's it. Whatever story and plot they manage to throw in is so un-engaging and unimpressive, compared to their premise of free world roaming, that no one really cares about moving the plot forward and the player ends up quitting it altogether -- after an insanely obsessive number of hours spent roaming (and enduring the mandatory Bethesda bugs). New Vegas was an improvement over 3, but it still doesn't quite match all that 1 and 2 did exceedingly well. Though the story, at least, is there, and wonderfully written and delivered.
It's a matter of preference, like it's been said before, and of what was the first Fallout you played, or the one that impressed you or suited your style best. I never played Tactics, even though I nabbed my free copy of it during the Farewell Fallout GOG Promo/Giveaway, because, honestly, everything bearing the word 'tactic' or any variation scares me to death. Tactic-squad-turn-base-strategic-plan-a-fight-like-an-army-general is not something I'm keen on experiencing, sorry. So, of the four I played, here's how I rank them:
1. Fallout 2 (I know, it isn't as innovative as the first one, and all that jazz, but I just got a bit more immersed in this one)
2. Fallout
3: Fallout: New Vegas
4. Fallout 3 (kill it with fire. Or even more aggressive than usual Radscorpions)
